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Full text of "Practical Organic Chemistry"

70

PRACTICAL ORGANIC CHEMISTRY

solution of sodium bisulphite (see Reaction 2, p. 67). The crystal-
line mass, C3H6ONaHS03, is filtered and well drained and then
distilled with sodium carbonate solution. The distillate is
dehydrated over solid calcium chloride and finally distilled.

Properties.—Colourless liquid with a pleasant colour ; b. p.
56*3° ; sp. gr. 0792 at 15° ; soluble in water.

Reactions.—I. Acetone gives the iodoform reaction like ethyl
alcohol5 (p. 50). 2. Dissolve a few crystals of /-bromophenyl-
hydrazine or /-nitrophenylhydrazine in a few drops of glacial
acetic acid, dilute with about i c.c. of water and add a drop of
acetone. The bromo- or nitro-phenylhydrazone of acetone
separate as crystalline precipitates.

•'

PREPARATION 8.
Chloroform (Trichloromethane), CHC13.
Liebig, Pogg. Ann.) 1831, 23, 444 ; Dumas, Ann. Chim. Phys.^
1834,56,115-                                                                                .*
200 grms. bleaching powder (fresh).
800 c.c. water.
40 grms. (50 c.c.) acetone.
A large round flask (4 litres) is fitted with a cork, through    .
which a bent tube passes connecting the flask with a long con-
denser and receiver.    The flask is placed upon a large sand-
bath.    Grind the bleaching powder into a paste with 400 c.c. of
water and rinse it into the flask with the remaining 400 c.c.
Add the acetone and attach the flask to the condenser.    Heat
cautiously until the reaction sets in, which is indicated by the      ^
frothing of the liquid.    Remove the flame for a time, and when
the reaction has moderated, boil the contents until no more
chloroform distils.    This is easily determined by collecting the
distillate in a test-tube and observing if any drops of heavy      j
liquid are present.   The distillate is shaken with dilute caustic
soda solution in a separating funnel and the lower layer of
chloroform run into a "distilling flask.    A. few pieces of solid
calcium chloride are added and left until the liquid is clear,
when it is distilled from the water-bath with a thermometer    >,
inserted into the neck of the flask.    Yield about 40 grams.